Louis Harold Gray

For other uses, see Louis Gray.

Louis Harold Gray FRS (10 November 1905 – 9 July 1965) was an English physicist who worked mainly on the effects of radiation on biological systems. He was one of the earliest contributors of the field of radiobiology.^[6] Amongst many other achievements, he defined a unit of radiation dosage (absorbed dose) which was later named after him as an SI unit, the gray.^[7][8]

Louis Harold Gray
LH Gray (left) and J Boag supervising construction of the Gray Laboratory at Mount Vernon Hospital in north London.
Born	(1905-11-10)10 November 1905 Richmond upon Thames, England
Died	9 July 1965(1965-07-09) (aged 59) Northwood, London[1]
Education	The Latymer School Christ's Hospital Trinity College, Cambridge
Known for	Bragg–Gray cavity theory Gray (unit)
Spouse	Frieda Marjorie Picot
Parents	Harry Gray (father) Amy Bowen (mother)
Awards	Roentgen Award Sylvanus Thompson Medal Barclay Medal Katherine Berkan Judd Award Bertner Foundation Award Fellow of the Royal Society[2]
Scientific career
Institutions	Cavendish Laboratory[3] Fellow of Trinity College Medical Research Council's Radiotherapeutic Research Unit at Hammersmith Hospital[4]
Thesis	(1930)
Doctoral advisor	James Chadwick[2]
Author abbrev. (botany)

Early life

Gray was born as an only child on 10 November 1905 to parents Harry and Amy Gray. His father worked at a post office.^[9]

Career

• 1933 - Hospital physicist at Mount Vernon Hospital, London
• 1936 - Developed the Bragg–Gray equation, the basis for the cavity ionization method of measuring gamma-ray energy absorption by materials^[10][11]
• 1937 - Built an early neutron generator at Mount Vernon Hospital^[12]
• 1938 - Studied biological effects of neutrons using the generator
• 1940 - Developed concept of RBE (Relative Biological Effectiveness) of doses of neutrons
• 1952 - Initiated research into cells in hypoxic tumors and hyperbaric oxygen
• 1953 - Oliver Scott established the British Empire Cancer Campaign Research Unit in Radiobiology^[13] at Mount Vernon Hospital with Hal Gray as director which in 1970 became the Cancer Research Campaign's Gray Laboratory and then (in 2001) the Gray Cancer Institute.
• 1953 - 1960 - Under Gray's direction, Jack W. Boag developed pulse radiolysis^[14]
• 1962 - Ed Hart, of Argonne National Laboratory, and Jack Boag^[15] discovered the hydrated electron using pulse radiolysis at the Gray Laboratory - This discovery initiated a new direction of research that is still very active today and is vital for understanding the effects of radiation on biological tissue, for instance in cancer treatment.

References

1. "LH Gray Memorial Trust: About L.H. Gray".
2. Loutit, J. F.; Scott, O. C. A. (1966). "Louis Harold Gray 1905-1965". Biographical Memoirs of Fellows of the Royal Society. 12 (2): 195–217. Bibcode:1966PMB....11..329.. doi:10.1098/rsbm.1966.0009. S2CID 73328020.
3. Rogers, J. D. (2013). The neutron’s discovery - 80 years on. Physics Procedia, 43. https://doi.org/10.1016/j.phpro.2013.03.001
4. Alma Howard (1965) Louis Harold Gray, International Journal of Radiation Biology and Related Studies in Physics, Chemistry and Medicine, 9:5, 509-511, DOI: 10.1080/09553006514550571
5. International Plant Names Index.  L.H.Gray.
6. Sekiya, Masaru; Yamasaki, Michio (2017). "Louis Harold Gray (November 10, 1905–July 9, 1965): a pioneer in radiobiology". Radiol Phys Technol. 10 (1): 2–7. doi:10.1007/s12194-016-0379-9. PMID 27714568. S2CID 207402619.
7. Louis Harold Gray F.R.S. - a chronology, CRUK/MRC Oxford Institute, 29 June 2000, archived from the original on 7 April 2014, retrieved 4 April 2014
8. Slipman, Curtis W.; Chou, Larry H.; Derby, Richard; Simeone, Frederick A.; Mayer, Tom G. (2008), Interventional spine: an algorithmic approach, Elsevier Health Sciences, p. 230–231, ISBN 978-0-7216-2872-1
9. Sekiya, Masaru; Yamasaki, Michio (1 March 2017). "Louis Harold Gray (November 10, 1905–July 9, 1965): a pioneer in radiobiology". Radiological Physics and Technology. pp. 2–7. doi:10.1007/s12194-016-0379-9. Retrieved 31 August 2023.
10. Gray, Louis Harold (1936). "An ionization method for the absolute measurement of gamma-ray energy". Proc. R. Soc. Lond. A. 156 (889): 578–596. Bibcode:1936RSPSA.156..578G. doi:10.1098/rspa.1936.0169.
11. Wynchank, S. (2017). Travel. In: Louis Harold Gray . Springer Biographies. Springer, Cham. https://doi.org/10.1007/978-3-319-43397-4_9
12. Alma, Howard (1965). "Louis Harold Gray". International Journal of Radiation Biology and Related Studies in Physics, Chemistry and Medicine. 9 (5): 509–511. doi:10.1080/09553006514550571. PMID 5319982.
13. Wynchank, S. (2017). Louis Harold Gray . Springer Biographies. Springer, Cham. https://doi.org/10.1007/978-3-319-43397-4_14
14. Hill, Kit (26 March 2007). "Obituary: Jack Boag". the Guardian. Retrieved 24 January 2023.
15. Boag, J. W.; Hart, E. J. (1963). "Absorption spectra in irradiated water and some solutions: Absorption spectra of 'hydrated'electron". Nature. 197 (4862): 45–47. Bibcode:1963Natur.197...45B. doi:10.1038/197045a0. S2CID 4277837.

External links

• Definition of RBE
• The LH Gray Memorial Trust founded in 1967
• Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology